Recently, technology for automating such tasks as is performed by a human under a specific environment has been rapidly advanced according to the development of various electronics such as computation technology, sensing technology and communication technology. In this situation, autonomous moving devices, which are devices automatically moving without being steered by a human, are also actively developed into practical use at present. Autonomous moving devices, which have been put to practical use, include an automatic carrier device, automatic cleaning device and security robot, which basically travel in an environment with a leveled and improved land. Autonomous moving devices, such as a rescue device or probe vehicle which moves on outdoor irregular ground, an autonomous driving vehicle which travels along a road, and a robot which works in a complex environment such as a station and office where humans exist, are expected to be put to practical use. Under such a situation, there has been growing demand for an obstacle avoidance technique which enables a moving device to move while autonomously avoiding an obstacle even when the obstacle exists in a working environment.
There have been disclosed a digital graph search method (for example, see PATENT DOCUMENT 1), a step search method (for example, see PATENT DOCUMENT 2), a potential method (for example, see PATENT DOCUMENT 3) and the like, as conventional technology for avoiding an unknown stationary obstacle in a local working environment. The digital graph search method is a technique for searching directions to reach a destination by dividing a working environment into fine grids and moving through only grids with no obstacle. The step search method is a technique for taking a detour around an obstacle by controlling a moving device in each step and selecting a point in a region with no obstacle as a next step. The potential method is a technique for controlling a moving device by use of a resultant force of a repulsive force from an obstacle and an attractive force from a destination on the assumption that there is a high potential field in an obstacle existence region while there is a low potential field in the destination. Especially in PATENT DOCUMENT 3, it is disclosed that a moving obstacle is avoided by using a probability potential field in which the existence probability of a moving obstacle is reflected in a potential field.    PATENT DOCUMENT 1: JP-A-2003-266349    PATENT DOCUMENT 2: JP-A-07-64633    PATENT DOCUMENT 3: JP-A-2003-241836